Local singer-songwriter Raoul Chazez was at an open mic this past Sunday where I was trying to learn how to be in two+ places at once, i.e., make sure the right red lights were on at the right time on the H6, and check 3 cameras were not out of batteries and still focused on the right thing. Batting a bit over .500 on the videos here, but the Zoom continues to be a remarkable piece of equipment.

This recording had 2 of 3 cameras semi-focused but one slightly mis-aimed. The 3rd (was the center) camera decided to de-focus on the previous performers' set and was high on a shelf where I couldn't see it, so it was basically lost for the rest of the night. Figured out I need a camera with remote control, including a view of what's being recorded. And it has to record on batteries for 3 hours. And cheap. And I'd like a pony, too.

Since the camera is in fixed position and the distance from the camera to the stage remains the same, you can focus on the stage (in the frontman) and then go to Manual focus. No way that you will loose focus again.

I'm going to try manual focus on at least one camera next time I do this venue. The problems I have in most places where I set up is that one or two of the cameras are put in locations where it's physically impossible to actually get behind the camera to really evaluate the focus well, and they're usually put there before people (the audience) are there, and then once the place fills up, I can't even really get to the cameras at all because I'd have to put a ladder in front of someone. Then, in something like an open mic, the number of performers change, and where they stand changes - some to the left, some to the right, some more forward, other more back. Add in low light where depth of field is not huge, I've been trying to let auto-focus on and hope. But, it's been a pretty big fail in a couple of cases, where it started Ok, but then went completely out of focus, so I'm going to do as you suggest, and see if that produces more usable "footage" (bittage?) by the end of the night. Thanks.

With Manual focus in this senario (fixed camera and steady distance from the subject) you will never loose focus if you focus on the subject correct.
You do not care about Left and Right movements in the stage, only for Back and Forward.
But if you look your lens manual you will see the depth of field it provides for specific mm setting and distance from the subject.
Wide angle lenses are better for this case, telephoto lenses will have narrow depth of filed for the same camera settings.
You can focus on a talent (friend of yours, place him in the spot you are interesting to be in focus).
You will set it and forget it.